Exploring Magnetocaloric Effects and Magnetic Properties in Lanthanide-Organic Frameworks
In the pursuit of advanced technological solutions, lanthanide-based materials are becoming pivotal in fields such as magnetic refrigeration and switchable molecular devices. Magnetic refrigeration offers an environmentally friendly alternative to conventional cooling methods by using magnetic materials for efficient temperature control. Meanwhile, switchable molecular devices harness the unique electronic and magnetic properties of lanthanides to enable responsive systems for data storage, sensing, and energy-efficient computing. Both fields stand to benefit significantly from the exotic magnetic properties exhibited by lanthanides; rare earth elements known for their unique magnetic features.
This PhD thesis investigates the potential of lanthanide-based materials, with a focus on their distinctive magnetic characteristics. Key findings include the discovery of a novel 2D triangular network structure, where weak magnetic exchange interactions lead to a significant magnetocaloric effect down to 0.4 K. Its effective performance at low magnetic fields highlights its promise as a candidate for low-temperature magnetic refrigeration, advancing the development of cooling technologies.
Additionally, the research explores "tunable valence tautomerism," demonstrating how the electronic states of samarium in a series of lanthanide-based materials were altered by external factors such as temperature. Incorporating ytterbium as a dopant into the samarium host structure further allowed for tuning the temperature at which the magnetic phase transition occurs, marking a significant advancement in switchable magnetic materials.
These findings open new opportunities for innovation in both magnetic refrigeration and switchable molecular devices. The ability to finely tune the magnetic properties of lanthanide-based materials holds great promise for developing more efficient cooling technologies and faster, more reliable electronic components.
Principal Supervisor:
Professor Kasper Steen Pedersen, DTU Chemistry
Co-supervisor:
Associate Professor Susanne Mossin, DTU Chemistry
Examiners:
Associate Professor Kaibo Zheng, DTU Chemistry
Associate Professor Carolina Sañudo, University of Barcelona, Spain
Professor Mark Murrie, University of Glasgow, Scotland